It is known to provide a cooling circuit for an internal combustion engine in which coolant is circulated between the engine and an external heat exchanger such as a radiator in the conventional manner.
Hybrid electric vehicles (HEVs) have one or more electric machines in addition to the internal combustion engine. The electric machines employed in HEVs typically also require a flow of coolant therethrough in order to prevent overheating. It is known to provide a HEV having a separate cooling circuit for cooling the electric machine.
It is against this background that the present invention has been conceived. Embodiments of the present invention may provide an improved cooling circuit for a HEV. Other aims and advantages of the invention will become apparent from the following description, claims and drawings.